Questions about DirectShow in FFMpeg

Questions involving a Windows version of FFmpeg.
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Videogamer555
Posts: 30
Joined: Sat Nov 09, 2013 1:16 am

Questions about DirectShow in FFMpeg

Post by Videogamer555 » Thu Sep 14, 2017 4:52 am

When dumping the list of devices with the command line "ffmpeg.exe -f dshow -list_devices true -i dummy>log.txt" I expected it to dump a text file called "log.txt" containing the list of DShow devices available. However, it just produces a blank text file, while displaying the list of devices in the console instead. The >log.txt syntax redircts StdOut to the text file, so it seems that the list of DShow devices in the console is being displayed via StdErr instead of StdOut, preventing the >log.txt syntax from working. Is there a way to get FFMpeg to output the list of DShow devices via StdOut, instead of StdErr?

And my second question is this. Is there a way to get FFMpeg to spawn my webcam's dialog box? You know, how with a webcam, there's often a dialog box (or some times 2 or 3 dialog boxes, each controls a different set of functionality) you can use to manually select things like frame rate, image size, brightness, contrast, enable/disable 60hz flicker reduction, etc. Is FFMpeg capable of spawning any of these dialog boxes?

Videogamer555
Posts: 30
Joined: Sat Nov 09, 2013 1:16 am

Re: Questions about DirectShow in FFMpeg

Post by Videogamer555 » Fri Sep 15, 2017 8:41 pm

Ok, I found a partial answer to my second question. It turns out that if you use this command line parameter "-show_video_device_dialog 1" it will spawn one of the dialogs. However, I still don't know how to spawn the other 2 (the one that lets you select frame rate and pixel format, as well as the one that lets you control the driver's parameters such as gain, exposure, auto color balance, mirror horizontally, etc),

I also still don't have an answer to my first question.

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